$ { \left[\begin{array}{r}{-1} \\ {0} \\ {0}\end{array}\right]-\left[\begin{array}{r}{2} \\ {1} \\ {4}\end{array}\right] = {?} } $
Solution: To find the difference of two matrices, subtract the corresponding items between each matrix. ${\left[\begin{array}{r}{-1}-{2} \\ {0}-{1} \\ {0}-{4}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{r}{-3} \\ {-1} \\ {-4}\end{array}\right]}$